Fan Ben Jiang reacts to a call in last season's playoffs against the Spurs.

Photo: Douglas Zimmerman, SF Gate

Fan Ben Jiang reacts to a call in last season's playoffs against...

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Oklahoma City Thunder fans erupt after Russell Westbrook hits a 3-pointer late in the fourth quarter against the Miami Heat in Game 1 of the NBA Finals at the Chesapeake Energy Arena in Oklahoma City, Oklahoma, on Tuesday, June 12, 2012. Oklahoma City won, 105-94. (Al Diaz/Miami Herald/MCT)

Photo: Al Diaz, McClatchy-Tribune News Service

Oklahoma City Thunder fans erupt after Russell Westbrook hits a...

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Stephen Curry (30) high fives fans in the second half. The Golden State Warriors played the San Antonio Spurs in Game 4 of the Wester Conference Semifinals at Oracle Arena in Oakland, Calif., on Sunday, May 12, 2013.

Photo: Carlos Avila Gonzalez, The Chronicle

Stephen Curry (30) high fives fans in the second half. The Golden...

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Fans cheer as the Warriors look to close out the fourth quarter with a big lead as the Golden State Warriors open their season against the Los Angeles Lakers at Oracle Arena in Oakland, CA Wednesday, October 30, 2013.

Thursday's game between the Warriors and Thunder at Oracle Arena is a matchup of two of the Western Conference's most talented teams, but it's also a matchup of two of the league's most passionate fan bases.

"Golden State and the fans at Oracle remind me a lot of the Seattle Seahawks' fans. They're loyal to a fault. Even when the team was bad, they always showed up. They've always been a raucous, loud crowd," TNT NBA analyst Reggie Miller said in a phone interview. "Having been in a small market for 18 years, I know how rabid those fans were in Indiana. That's exactly what you get in Oklahoma City. The Thunder are the only show in town, and their fans are loud.

"I get how both fan bases could claim to be the best."

Oklahoma City got the early nod as the league's general managers voted Chesapeake Energy Arena to grant the best home-court advantage, according to NBA.com's preseason survey. But the Warriors' fans at Oracle Arena made up quite a bit of ground after their team's unexpected playoff run last season.

Last year, 21 of the NBA's 30 general managers voted for Oklahoma City, Miami and Utah each got three votes, and Denver, Portland and the Lakers each received one. This year, the vote was much closer with Oklahoma City's 11 votes leading the way, followed by the Warriors (eight), Denver (four), Miami (three), and Chicago and Utah (two each).

The difference between Nos. 1-2 might be even closer by the time the Warriors play at the Thunder on Nov. 29 or when the teams complete the season series in Oklahoma City on Jan. 17. TicketCity used an algorithm based on social media metrics, game attendance and exclusive ticket dates to contrast all NBA teams and found that the Warriors have one of the most engaged and growing fan bases in the league.

"Oklahoma City reminds me a lot of Portland, back when it was Rip City. It's the only pro team in the city, and those people really come out and support it," said Warriors backup centerJermaine O'Neal, who is playing for his seventh team in his 18th NBA season. "Those guys do a really good job in Oklahoma City, but I think our home crowd is probably the loudest. It's very difficult to come inside of Oracle and get a win, because of the energy that's inside the building."

With a college-cheering-section feel, the Thunder fans happily wear matching T-shirts given out at games and stand until opponents score. Sometimes they just keep standing, cheering and refusing to leave - even after the season is over.

In 2010, there was a moment of heartbreak after Russell Westbrook's potential game-winning shot missed at the buzzer. But then the crowd stood and roared for 2 minutes and 32 seconds, celebrating the effort their guys gave in taking the top-seeded Lakers to six games in the first round.

Oklahoma City is 3-0 as the host this season, a year after going 34-7 and registering a league-best 13 points per game differential on its home floor. The Warriors look like a similar group this season, having led each of their three visiting opponents by at least 27 points and trailing by a combined 23 seconds in winning the first three games of the season at Oracle.

But even when the Warriors weren't running opponents off of the home floor, the fans were in the home seats. Sure, they've sold out 41 consecutive games, but the average attendance hasn't dropped below 18,000 per game since 2004-05. The Warriors had a playoff drought from 1995 to 2006, during which they won an average of 27.7 games per season, but at least 12,200 fans always showed and screamed.

"This city has had a lot of hard times, trying to find a good team over many, many years," O'Neal said. "But they've consistently come out and supported their team. You don't find that a lot."

Only at "Roaracle."

Warriors (5-3) vs. Thunder (5-2)

Where: Oracle Arena

When: 7:30 p.m.

TV/Radio: TNT/680

Of note: The Warriors haven't won a season series against the Thunder since the franchise moved from Seattle to Oklahoma City before the 2008-09 season. ... Thunder center Kendrick Perkins is expected to miss the game because of the death of his grandfather. ... Point guard Russell Westbrook has showed no ill signs since returning for the third game of the season from surgery to repair a lateral meniscus tear in his right knee. ... Forward Kevin Durant has averaged 30.4 points, 8.7 rebounds and 4.9 assists in 21 games against the Warriors.